get_temp_filename_for()

read_state()

Name of state file is the same as filename of WAL segment being archived, but it is in state-dir.

save_state()

Helper function to save state to state-file.

read_args_specification

Defines which options are legal for this program.

read_args_normalization

Function called back from OmniPITR::Program::read_args(), with parsed args as hashref.

Is responsible for putting arguments to correct places, initializing logs, and so on.

validate_args()

Does all necessary validation of given command line arguments.

One exception is for compression programs paths - technically, it could be validated in here, but benefit would be pretty limited, and code to do so relatively complex, as compression program path might, but doesn't have to be actual file path - it might be just program name (without path), which is the default.